Question

If the base-dissociation constant, Kb, for a substance is 4.3 mc021-1.jpg 10–10, what does this tell you about Ka?
Use mc021-2.jpg.
Ka = 2.3 mc021-3.jpg 10–5
Ka = 1.0 mc021-4.jpg 10–4
Ka = 2.3 mc021-5.jpg 102
Ka = 1.0 mc021-6.jpg 103

Answer 1

Use Ka · Kb = Kw. At 25 °C, Kw = 1.0×10^−14, so

Ka = Kw / Kb = (1.0×10^−14) / (4.3×10^−10) = 2.33×10^−5 ≈ 2.3×10^−5.

So the correct choice is Ka = 2.3 × 10^−5.